It is known in the art of conveyor belts to have endless belt conveyor assemblies. Usually, this construction is made by providing apertures in the front and back hinge parts of a belt link perpendicular to the travelling direction. By overlapping the hinge parts of two adjacent chain or belt links, and inserting a transverse rod through the apertures, thereby connecting two adjacent links in a hinge-like manner, the two adjacent links will begin to form a conveyor belt.
Such prior art constructions are known from, for example, EP 427337, EP 1306323, and others.
Conveyor belts that incorporate one or more rollers are also known in the art. These types of conveyors are utilized where items are transported from a first station to a second station, and where the second station may not be able to handle the items as quickly as they are forwarded to this station. Therefore, instead of having to slow down the conveying belt or stop the belt all together, the conveying belt is provided with means such that the conveyor belt may continue to rotate and the articles or items transported on the conveying belt will remain in place regardless of the continued circulation of the conveying belt.
These types of accumulating conveying belts have also been designed such that some of the prior art devices may have means arranged below the upper run of the conveyor belt which may be activated such that the rollers provided in or on the conveying belt may be brought to rotate in a direction that is different from the general direction of the conveying belt whereby objects or items transported on the main conveying belt due to the odd angle of rotation of the rollers will be transported in a direction not parallel to the general transport direction of the main conveying belt.
Examples of conveying belt structures of the type mentioned above are known, for example, EP 1398282, WO 2005/073111, U.S. Pat. No. 6,148,990, and EP 1367009.
EP 1367009, which uses the same basic structure as disclosed in EP 1398282, comprises a number of links where the links include a number of rollers that are layered by means of axles in apertures provided in the links. Each link comprises an upper and a lower link section where means for accommodating the axle around which the roller rotates are provided in both the upper and the lower link. The axle has a roller mounted around the axle and positioned in an accommodating means at the desired angle in, for example, the lower link. When all the rollers and corresponding axles have been placed at the desired orientations in the accommodating means provided in the lower link, the upper link is superposed on top of this and assembled either by special assembly means or by inserting a pin through eye parts provided at the leading and trailing edge of each link such that a traditional conveyor belt assembly may be achieved. The axle accommodating means is provided with a certain degree of play such that the rollers due to gravity will be at the lower part of the accommodating means in which position the rollers will not extend beyond the top surface of the conveyor belt. By providing rails at predetermined positions underneath the upper run of the conveyor belt, these rails will force the rollers upwards and thereby force the axle to the upper end of the accommodating means, in which the rollers will extend above the surface of the conveyor belt such that the accumulating capability of the conveyor belt or the side tracking of the items on the conveyor belt may be achieved. By arranging the rails and actuating the rails underneath the upper run of the conveyor belt, it is possible to control and guide items/objects transported on the upper side of the conveyor belt to certain locations as may be desired. This allows the transfer of items to an adjacent conveyor belt or to singulate the items, i.e., by forcing them towards the central part whereby the items will intermesh and substantially form a single file.
In WO 2005/073111, a system is disclosed where rollers or balls may be arranged in belt links and maintained in position by a retainer ring such that once the roller has been arranged in the desired position, the retainer ring will be welded onto the belt link and thereby fixing the angle at which the roller axle of the roller is arranged in relation to the general transport direction of the conveying structure. In embodiments where balls are used, the retainer ring is fastened around the ball such that the ball will extend above the surface of the conveying belt by different fastening means such as welding, screwing, or tap engagement means between the retainer ring and the belt link.
A system of retainers is also used in U.S. Pat. No. 6,148,990 in order to retain the balls in apertures provided in the belt link. The retainer members may be fastened for example by clicking the retainer into engagement with the belt link. In other embodiments, rollers may be arranged in cup shaped holders which may be accommodated inside the belt link in order to provide for the accumulating feature. When the system of cups is used, a substantially universal orientation of the rollers may be achieved simply by orientating the cups in the desired position. This prior art also drives a system of axles and rollers where the rollers are imbedded in apertures provided, in particular, in the upper part of a belt link and the axles are inserted from underneath in through going bores in the belt link which may be superposed with a through going hole in the roller such that the roller may be arranged and the axles held in the belt link by appropriate holes in the belt link's structure.
Common for the above mentioned prior art techniques is the fact that the assembly of the belt links with the rollers is quite cumbersome. In the instances where pins need to be inserted through a roller superposed with further holes in the belt link, a time consuming and labor-intensive process is needed. Furthermore, from a hygienic point of view, it is highly undesirable to have items arranged in the conveying belt structure which may not be readily accessed. Common for all the samples of embedding rollers or balls in belt link structures where retainer means, either retainer rings or retainer members are used, is the fact that none of the links are easy to clean. They require quite costly and labor-intensive assembly procedures. In the case of breakage, it is more economical to replace the entire belt link than simply replace one single roller.
Also the common problem with the prior art devices is the fact that when it is desirable to activate the rollers such that objects are transported in a direction different from the general transport direction of the conveying belt, this is achieved by arranging a number of rails underneath the surface of the upper run of the conveying belt. Where the rollers are installed as suggested in WO 2005/073111, EP 137009, and EP 398282, it is substantially impossible to alter the transport direction because the rollers are welded or in other ways inaccessibly arranged in the link.
Finally, when it is desirable to utilize these types of conveying belts within the food industry, none of the prior art devices are able to fulfil the high requirements of cleanliness. The retaining members of the prior art devices accumulate dust and debris from the goods transported on the conveying belt which may be potential beds for bacteria growth or other possible contamination sources. Further, the rollers mounted by inserting pins across the entire belt link, the apertures provided in the belt link and surrounding the pins have historically proven to be quite impossible to clean. Also common for the four types of prior art devices mentioned above is the fact that the conveyor belt is assembled from a number of substantially identical belt links. The belt links include recesses and eye parts along the leading and trailing edges. Recesses and eye parts are offset in relation to each other such that the eye parts along the leading edge may be inserted into the recesses along the trailing edge of the adjacent link. Apertures provided perpendicular to the transport direction in the eye parts may be superposed such that an insertion of a pin will connect two adjacent belt links in a hinge-like manner. This type of assembly is quite common within the technical field and has proved again and again that to be extremely difficult and very costly to attain and maintain at a high standard of hygiene.
It is consequently an object of the present invention to alleviate these disadvantages and provide a conveying belt structure made up from a number of substantially identical belt links where easy and easily accessible rollers are provided and pin-less connections used in order to connect adjacent belt links.